This invention relates to an air intake device for an engine and more particularly to an improved high efficiency and compact induction system for an engine.
It is well known that the efficiency of the induction system of an internal combustion engine can be significantly improved by tuning the length of the intake passages which serve the individual intake ports. Also, it is known that the induction system efficiency can be improved by providing a common plenum chamber that serves all of the intake passages or at least groups of them so as to reduce cylinder to cylinder variations. However, the provision of tuned intake passages and a plenum chamber can give rise to obvious spatial difficulties. This problem is particularly acute in motor vehicle applications wherein the engine compartment tends to be very compact due to the number of accessories and ancillary components of the vehicle which are mounted therein. Also, the induction system should be arranged in such a way so that there will be adequate air flow across the induction system so that the induction system does not become heated and reduce the volumetric efficiency of the engine. Previously proposed induction systems have not been fully capable of meeting all of these requirements.
For example, it has been proposed to provide a serpentine shaped intake passage for each intake port so as to increase the length of the intake passages. Such an arrangement, however has necessitated the wrapping of the intake passages around the plenum chamber and thus preventing its adequate cooling.
It is, therefore, a principal object of this invention to provide an improved, compact, high efficiency induction system for an engine.
It is a further object of this invention to provide an induction system for an engine in which long intake runners can be employed along with a plenum chamber and yet a compact and adequately cooled construction results.
In addition to the difficulties aforenoted, the complex configurations of previously proposed induction systems have made them very expensive to manufacture. It is, therefore, a still further object of this invention to provide an improved induction system for an engine that can be easily and inexpensively manufactured.
In connection with the tuning of the intake system, frequently it may become desirable to tune a given engine in a different manner by changing the length of the intake passages. With previously proposed constructions, this has necessitated the complete replacement of the entire induction system.
It is, therefore, a still further object of this invention to provide an improved, compact, efficient induction system wherein the length of the intake passages can be easily changed to suit particular applications.
As has been previously noted, the engine compartment frequently contains a number of accessories and ancillary components not only for the engine, but also for the associated motor vehicle. Frequently, many of these accessories must be driven from the engine and this further complicates the positioning and design of the induction system.
It is, therefore, a still further object of this invention to provide an improved, high efficiency induction system for an engine that is compact and which yet will afford adequate space for accessories driven by the engine.